Hub assemblies for bicycle wheels, and in particular hub assemblies for the front wheel of a bicycle have traditionally utilized ball bearing structures as a way of providing rotational movement of the hub and wheel with respect to a stationary or fixed axle. To that end, the hub body of a traditional hub assembly includes a center section with hub flanges attached at either end and a hollow bore extending therethrough. The wheel axle extends through the hollow bore and has threaded ends. The hub flanges include openings around their periphery for accepting one end of the wheel spokes while the flange also serves as an outer or a rotating bearing race to hold the hub bearing structures. Cone nuts are threaded onto each end of the axle and hold the ball bearing structures within the respective hub flange. Portions of the cone nuts also serve as inner or stationary bearing races. The threading of the cone nuts onto the axle determines the force in which the bearing structure is held in the bearing race of the hub flange.
Accordingly, in the manufacture of a hub assembly, one of the operational steps involves advancing the cone nuts onto the threaded axle ends until the proper bearing adjustment is achieved between the inner and outer bearing races. The proper bearing adjustment must be maintained during the packaging and shipping of the hub to a bicycle manufacturer, during the building of the bicycle wheel by the bicycle manufacturer, and during shipping of the finished bicycle to a retailer. The retailer, and sometimes the end consumer, are customarily required to assemble the front bicycle wheel to the front fork after they have purchased the bicycle.
Attachment of the front wheel to the front fork of the bicycle requires correct positioning of each end of the axle into the corresponding ends of the front fork. Additionally, components such as wheel retainers, fender braces and other parts are installed onto the ends of the axle, and then two outside nuts are assembled onto each end of the axle to secure the wheel and hub to the fork. If the hub bearing structure has developed unacceptable looseness or play after a normal period of usage, the cone nuts may be re-adjusted by first loosening the outside nuts which attach the front wheel to the fork and adjusting the cone nuts. The outside nuts may then be retightened.
Generally, during assembly of a bicycle hub, the cone nuts are advanced onto the threaded end portions of the axle which extend beyond both ends of the hub body. Once the cone nuts have been threaded into their final adjusted position and the bearing structures are secured to the outer bearing races within the hub flanges, the cone nuts are locked or otherwise fixed at that position. Various ways of locking the cone nuts into position on a bicycle axle have been developed. The method of Schwinn U.S. Pat. No. 2,290,451 utilizes two separate lock nuts which must be tightened against each cone nut. A second locking method is generally illustrated in Dian U.S. Pat. No. 3,131,008, Christian et al.; U.S. Pat. No. 3,428,377; and Humlong U.S. Pat. No. 3,858,942. These patents discuss manufacturing an axle in such a way as to provide resistance which the internal threads of the cone nuts must encounter prior to reaching their final adjusted position. Alternatively, Hsieh U.S. Pat. No. 5,292,287 makes one cone nut an integral part of the axle while the other cone nut is threaded on the axles.
One of the most economical ways to manufacture a bicycle hub assembly and to lock the cone nuts into their final adjusted position such that they may be easily re-adjusted before and after assembly to a bicycle fork is to independently tighten each cone nut onto the axle. For example, the first method discussed above requires two additional lock nuts. The third method requires forming the first cone nut as an integral part of the axle, and after the integral cone nut is formed, threading of the axle is made more difficult. Furthermore, the third method limits the bearing adjustment of the hub assembly once it is installed on the bicycle, because only one cone nut is adjustable.
In assembling a bicycle hub wherein the cone nuts are independently adjustable and lockable, the first cone nut is threaded onto the first threaded end of the axle and is stopped at a predetermined distance from the endmost point of the axle. The second cone nut is advanced onto the second threaded end of the axle, meeting axle resistance, and advancement of the second cone nut is ceased when the proper bearing adjustment is obtained in the hub assembly. While the second cone nut is being advanced on the threaded end of the axle, the axle and first cone nut are held stationary and kept from rotating by holding the first cone nut at its wrench flats. When the hub assembly is complete, the hub should preferably have the two threaded ends of the axle extending approximately equal distances past the cone nuts.
However, achieving equal extension of the axle ends past the two cone nuts is often difficult. Frequently, when the second cone nut is being advanced on the axle the resistance encountered by that cone nut is greater than the resistance which was encountered by the first cone nut. When that occurs, the second cone nut ceases to turn with respect to the axle and additional rotation of the second cone nut causes the axle to rotate instead with respect to the first cone nut. When the rotation of the second cone nut is ceased because the proper bearing adjustment is obtained, the constructed hub assembly has two threaded axle ends which extend different amounts past the two cone nuts. This could provide difficulty in assembling the bicycle wheel to the front fork of a bicycle.
Accordingly, there is a need for a hub assembly in which an axle may be secured with independently rotating cone nuts and which consistently yields a completed hub with an axle that projects equal amounts past the two cone nuts. Further, it may be desirable to have different predetermined lengths of the axle projecting past the cone nuts. The predominant solution has been to physically restrain the first cone nut and physically restrain the axle in order to prevent the first cone nut from advancing any further onto the axle. As may be appreciated, restraining the axle further complicates the assembly process. Therefore, it is an objective of the present invention to provide a hub assembly which utilizes independently adjusted cone nuts which may be assembled with an axle into a completed hub and which will yield equal extension of the axle ends with respect to both of the cone nuts. It is another objective to provide such a hub assembly which may be assembled easily, efficiently, and without requiring that the axle be restrained during assembly.